This invention relates to a hydraulic brake system for vehicles, particularly automotive vehicles and is of the type which includes a mass inertia-actuated device for a deceleration and transverse acceleration dependent control of the braking force distribution.
Known hydraulic brake systems of the above-outlined type are technically and constructionally complex and expensive and require significant space. Further, as a rule, during brake actuation in curves, the braking pressure of the two rear wheels is reduced or limited as a function of transverse accelerations. Since this effect applies to both the inner and outer wheel in the curve, the braking forces are not utilized to the fullest extent.
Thus, German Patent No. 1,160,744 discloses a hydraulic brake system which comprises a control mass executing longitudinal and transverse excursions in a pendulum-like manner. The control mass which thus has several degrees of freedom of motion, effects, by means of a mechanical linkage system, a longitudinal and transverse acceleration-dependent braking force reduction of the rear wheel brakes relative to the front wheel brakes.
German Offenlegungsschrift (Application Published Without Examination) No. 1,555,095 discloses a hydraulic brake system which comprises a spherical control mass having several degrees of freedom, that is, the mass is movable in the longitudinal and transverse direction of the vehicle, in order to effect a longitudinal and transverse acceleration-dependent braking force reduction of the rear wheel brakes.
Further, German Offenlegungsschrift No. 1,630,405 discloses a hydraulic brake system in which the braking pressure is limited or reduced only at the inner wheel. In this known brake system, in the brake lines leading to the rear wheel brakes, there are arranged separate solenoids which are separately energized by means of a signal transmitter which responds only in a certain predetermined direction (such as a directional transverse force sensor). When the brakes are applied in curves, upon exceeding a predetermined transverse acceleration force, only that solenoid is energized which is associated with the inner rear wheel, while the solenoid arrangement in the other brake circuit (associated with the outer wheel) does not respond. Although theoretically it is readily feasible to sense deceleration and acceleration forces in the longitudinal and transverse direction of the vehicle and utilize them for generating control signals for electrically actuated valve arrangements, the use of such electronic and electric devices in a hydraulic system not only further complicates the brake system but also introduces additional sources of error.